1. Field of the Invention
The present invention relates to an inspection apparatus for gas detection, particularly to an inspection apparatus which can repeatedly supply a target gas in different concentration to gas detectors for testing the performance and accuracy of the gas detectors during a shorter period and can reduce the amount of gas required.
2. Related Prior art
The known system for examining the accuracy or performance of a gas detector is performed in an open environment. In such a method, a standard gas is first mixed with a diluting gas in a blending reservoir at a proper proportion and then is continuously sent through a gas detector to be inspected so as to serve as a testing gas to the gas detector.
In such an inspection apparatus, the environment around the gas detector is an open one and thus is unstable and uncontrollable due to its ease change with the changes of the atmosphere, such as pressure or the like. Moreover, while changes the concentration of the standard gas to inspect the action of the gas detector under different gas concentration, the gas required to reach the equilibrium of that concentration is approximately ten times more than the volume of the blending reservoir. Including the amount of the gas required to perform the test within a period of time, the total amount of gas consumption will be approximately twenty times more than the volume of reservoir. Thus, it is not only a waste of standard gas and diluting gas, but also a waste of time. Furthermore, releasing the tested gas to atmosphere could create an air pollution problem. It is specially harmful in the case that such a testing gas is toxic.